spi: convert drivers to use bits_per_word_mask

Fill in the recently added spi_master.bits_per_word_mask field in as
many drivers as possible. Make related cleanups, such as removing any
redundant error-checking, or empty setup callbacks.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/drivers/spi/spi-au1550.c b/drivers/spi/spi-au1550.c
index 44dd34b..d736fa9 100644
--- a/drivers/spi/spi-au1550.c
+++ b/drivers/spi/spi-au1550.c
@@ -248,11 +248,6 @@
 			hz = t->speed_hz;
 	}
 
-	if (bpw < 4 || bpw > 24) {
-		dev_err(&spi->dev, "setupxfer: invalid bits_per_word=%d\n",
-			bpw);
-		return -EINVAL;
-	}
 	if (hz > spi->max_speed_hz || hz > hw->freq_max || hz < hw->freq_min) {
 		dev_err(&spi->dev, "setupxfer: clock rate=%d out of range\n",
 			hz);
@@ -296,12 +291,6 @@
 {
 	struct au1550_spi *hw = spi_master_get_devdata(spi->master);
 
-	if (spi->bits_per_word < 4 || spi->bits_per_word > 24) {
-		dev_err(&spi->dev, "setup: invalid bits_per_word=%d\n",
-			spi->bits_per_word);
-		return -EINVAL;
-	}
-
 	if (spi->max_speed_hz == 0)
 		spi->max_speed_hz = hw->freq_max;
 	if (spi->max_speed_hz > hw->freq_max
@@ -782,6 +771,7 @@
 
 	/* the spi->mode bits understood by this driver: */
 	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
+	master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 24);
 
 	hw = spi_master_get_devdata(master);